Point D on side AB of triangle ABC is chosen so that AD = AC. It is known that the angle CAB = 13 degrees and the angle ACB = 143 degrees. Find the DCB corner.
Since, by condition, AD = AC, the ACD triangle is isosceles with the base CD.
Then the angle ADC = ACD.
The sum of the inner angles of the triangle is 180, then the angle ADC = ACD = (180 – CAB) / 2 = (180 – 13) / 2 = 83.5.
Then the angle DСВ = АСВ – АСD = 143 – 83.5 = 59.5.
Answer: The value of the angle DCB is 59.5.
One of the components of a person's success in our time is receiving modern high-quality education, mastering the knowledge, skills and abilities necessary for life in society. A person today needs to study almost all his life, mastering everything new and new, acquiring the necessary professional qualities.